/*******************************************************************************
 * Copyright 2017 Bstek
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.  You may obtain a copy
 * of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations under
 * the License.
 ******************************************************************************/
package com.bstek.urule.console.servlet.flow;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.StringUtils;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import com.bstek.urule.exception.RuleException;
import com.bstek.urule.Utils;
import com.bstek.urule.console.repository.RepositoryService;
import com.bstek.urule.console.repository.model.ResourcePackage;
import com.bstek.urule.console.servlet.RenderPageServletHandler;
import com.bstek.urule.model.flow.FlowDefinition;
import com.bstek.urule.parse.deserializer.FlowDeserializer;

/**
 * @author Jacky.gao
 * 2016年6月3日
 */
public class RuleFlowDesignerServletHandler extends RenderPageServletHandler {
    private RepositoryService repositoryService;
    private FlowDeserializer flowDeserializer;

    @Override
    public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String method = retriveMethod(req);
        if (method != null) {
            invokeMethod(method, req, resp);
        } else {
            VelocityContext context = new VelocityContext();
            context.put("contextPath", req.getContextPath());
            String file = req.getParameter("file");
            String project = buildProjectNameFromFile(file);
            if (project != null) {
                context.put("project", project);
            }
            resp.setContentType("text/html");
            resp.setCharacterEncoding("utf-8");
            Template template = ve.getTemplate("html/rule-flow-designer.html", "utf-8");
            PrintWriter writer = resp.getWriter();
            template.merge(context, writer);
            writer.close();
        }
    }

    public void loadFlowDefinition(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        InputStream inputStream;
        String file = req.getParameter("file");
        String version = req.getParameter("version");
        file = Utils.decodeURL(file);
        try {
            if (StringUtils.isEmpty(version)) {
                inputStream = repositoryService.readFile(file, null);
            } else {
                inputStream = repositoryService.readFile(file, version);
            }
            Element root = parseXml(inputStream);
            FlowDefinition fd = flowDeserializer.deserialize(root);
            inputStream.close();
            writeObjectToJson(resp, new FlowDefinitionWrapper(fd));
        } catch (Exception ex) {
            throw new RuleException(ex);
        }
    }

    protected Element parseXml(InputStream stream) {
        SAXReader reader = new SAXReader();
        Document document;
        try {
            document = reader.read(stream);
            Element root = document.getRootElement();
            return root;
        } catch (DocumentException e) {
            throw new RuleException(e);
        }
    }

    public void loadPackages(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String project = req.getParameter("project");
        try {
            List<ResourcePackage> packages = repositoryService.loadProjectResourcePackages(project);
            writeObjectToJson(resp, packages);
        } catch (Exception ex) {
            throw new RuleException(ex);
        }
    }

    public void setRepositoryService(RepositoryService repositoryService) {
        this.repositoryService = repositoryService;
    }

    public void setFlowDeserializer(FlowDeserializer flowDeserializer) {
        this.flowDeserializer = flowDeserializer;
    }

    @Override
    public String url() {
        return "/ruleflowdesigner";
    }
}
